A content analysis exploring adaptive cruise control and forward collision warning systems in vehicle manuals

Despite advancements in vehicle technology such as adaptive cruise control (ACC) and forward collision warnings (FCW), rear-end crashes remain an overrepresented crash type. Given the increasing penetration rate of ACC and FCW, it is timely to explore the functions, limitations, and customisations of these systems as specified in vehicle manuals. The current study employed a content analysis to explore a) whether these systems align with recommended safe following distances and b) whether limitations of these systems are related to areas associated with rear-end crashes. A sub-group of the top 200 registered vehicles in Queensland, Australia ( n = 55 models) were represented in the content analysis. After removing ineligible vehicles (i.e., registrations of a non-motor vehicle, not manufactured during 2013–2023) and sourcing vehicle manuals (i.e., from Australian manufacturers and third-party websites, email requests to manufactures), a total of 41 models (20 makes) were included. Extracted data was coded to reflect the functions, limitations, and customisable features of these systems. Findings identified a small number of ACC systems aligned with the recommended safe following distance, with the remaining manuals providing insufficient or ambiguous information. Both ACC and FCW systems were limited in common driving situations, including conditions known to contribute to rear-end crashes. Reliance on drivers to use ACC only in appropriate conditions may lead to improper use, reducing the effectiveness of this system in reducing rear-end crashes. Moving forward, it appears warranted that information on ACC and FCW is consistent across manuals to provide drivers with clear and comprehensive detail.